History of detection of the core

• the existence of the core: by using seismic waves (velocity of P-waves smaller in the core region): Oldham (1906),

• the existence of the CMB: by using seismic waves (discontinuity in P-wave velocity profile): Gutenberg (1913),

• the fluidity of the core: by using earth tides and seismic waves: Jeffreys (1926),

• the existence of an inner core: by using seismic waves: Lehmann (1936),

• the concept of geodynamo: Elsasser (1946).